1. Field of the Invention
The present invention relates to an information processing apparatus, image sensing apparatus, control method, and recording medium, and particularly to generation of image data to which input response characteristic conversion processing complying with the Academy Color Encoding Specification is applied.
2. Description of the Related Art
Recently, images and moving images serving as digital data are presented to viewers in various scenes including a movie show. When an image to be presented is data imaged by an image sensing apparatus such as a digital camera, the image represents a color output corresponding to the characteristic of the image sensing apparatus. That is, the image represents a different color response under the influence of the model or individual difference of the image sensing apparatus, an optical member such as a lens mounted in imaging, applied conversion processing, or the like. In this manner, the color response of image data changes depending on conditions in imaging. Especially when image data are sequentially presented by using an image presentation apparatus such as a projector at a screening of a movie, different impressions may be given to viewers between images obtained under different conditions in imaging.
To solve this, in creation/editing of digital data of a movie to be screened, different color conversion processes are applied for respective image sensing apparatuses used in imaging so as to exhibit, for example, a uniform color response in the same scene. That is, processing of removing (or reducing) a change of the color response arising from the individual difference or settings of an image sensing apparatus or the like is applied. The Academy of Motion Picture Arts and Sciences of America (to be referred to as the Academy hereinafter) has proposed the Academy Color Encoding Specification (ACES) which defines an ideal color response function or the like by an image sensor. This specification includes implementation of a uniform color response independent of conditions in imaging. More specifically, conversion into a color balance complying with an ideal color response function is implemented by performing, on image data, Input Device Transform (IDT) processing considering various parameters in imaging.
ACES IDT processing requires parameters (imaging parameters) representing conditions in imaging for respective image data. Factors which deviate, from an ideal color response function, the color balance of image data obtained by imaging are, for example, the difference of the image sensor, the lens tint and applied color filter in imaging, and a correction parameter applied to image data. In IDT processing, an IDT conversion coefficient is decided in accordance with imaging parameters serving as these deviation factors. The decided IDT conversion coefficient is applied to image data to convert it into image data corresponding to an ideal color response function.
However, there has not been an image sensing apparatus which outputs, for IDT processing in an external apparatus, imaging parameters necessary to decide an IDT conversion coefficient. Japanese Patent Laid-Open No. 2002-010178 has disclosed a technique of adding, to image data, imaging parameters including attribute information such as exposure information. However, these imaging parameters cannot be used in IDT processing, unlike the above-mentioned parameters necessary to decide an IDT conversion coefficient. For example, when editing a video, the user needs to decide an IDT conversion coefficient by referring to conventional imaging parameters, and apply IDT processing to image data in an external apparatus.